📚 Year 10 Eduqas Biology: Case Study Practical Workouts | Year 10 Eduqas 生物：案例分析实战演练
In Year 10 Eduqas Biology, case studies are not just about memorising facts — they require you to apply scientific knowledge to unfamiliar scenarios, interpret data, and justify your reasoning. This article presents a series of practical workouts designed to sharpen your case study skills, mirroring the style of exam questions you will face. By working through these examples, you will learn how to approach data analysis, experimental evaluation, and application of biological principles with confidence.
在 Year 10 Eduqas 生物课程中，案例分析不仅仅是对事实的记忆，它要求你将科学知识应用于陌生情境、解读数据并证明推理过程。本文提供一系列实战演练，模拟你将在考试中遇到的题型，旨在强化你的案例分析技巧。通过逐步完成这些示例，你将学会如何自信地处理数据分析、实验评估以及生物学原理的应用。
1. Understanding the Case Study Approach in Eduqas | 理解Eduqas案例分析方法
Case study questions in Eduqas often present a short scenario — for example, a description of an experiment, a disease outbreak, or an environmental investigation. You are then asked to analyse the data provided, suggest explanations, identify limitations, and sometimes propose improvements or further investigations. The key is to use your core biological knowledge to unpack the scenario, rather than simply recalling a textbook definition.
Eduqas 考试中的案例分析题通常会提供一个简短情境，例如描述一项实验、一次疾病暴发或一项环境调查。然后要求你分析所提供的数据、提出解释、识别不足之处，有时还需要建议改进方案或进一步探究。关键在于运用你的核心生物学知识来解构情境，而不是仅仅回忆课本定义。
Always read the stem carefully and underline the command words: ‘describe’, ‘explain’, ‘evaluate’, ‘suggest’. ‘Suggest’ is particularly common in case studies because it tests your ability to apply logic to new situations. For instance, you may be asked to suggest why a particular enzyme stopped working at high temperature, which requires you to think about denaturation and active site shape.
务必仔细阅读题干，并标记指令词：“描述”、“解释”、“评估”、“建议”。“建议”在案例分析中尤为常见，因为它考查你将逻辑应用于新情境的能力。例如，你可能会被要求建议为什么某种酶在高温下停止工作，这需要你思考变性作用和活性位点形状的改变。
2. Case Study 1: Enzyme Activity and pH | 案例1：酶活性与pH
A student investigated the effect of pH on the activity of catalase extracted from potato tissue. Catalase breaks down hydrogen peroxide into water and oxygen. The student used an upturned measuring cylinder to collect the volume of oxygen produced in 60 seconds at different pH values, controlled using buffer solutions. The results are shown in the table below.
一名学生研究 pH 对从马铃薯组织中提取的过氧化氢酶活性的影响。过氧化氢酶将过氧化氢分解为水和氧气。该学生使用倒置量筒收集在不同 pH 值下 60 秒内产生的氧气体积，pH 值通过缓冲溶液控制。结果如下表所示。
| pH | Volume of oxygen / cm³ |
|---|---|
| 4.0 | 5 |
| 5.0 | 18 |
| 6.0 | 34 |
| 7.0 | 47 |
| 8.0 | 30 |
| 9.0 | 9 |
Describe the pattern shown in the table. The rate of oxygen production increases as pH rises from 4 to 7, reaching a maximum at pH 7. Beyond pH 7, the volume of oxygen produced decreases sharply. This suggests that catalase from potato has an optimum pH around 7, which is near neutral.
描述表中显示的模式。随着 pH 从 4 升至 7，氧气产生速率增加，在 pH 7 时达到最大值。超过 pH 7 后，产生的氧气体积急剧下降。这表明马铃薯中的过氧化氢酶最适 pH 约为 7，接近中性。
Explain why enzyme activity falls at pH 9. Enzymes are proteins with a specific three-dimensional shape. The active site is held in place by ionic and hydrogen bonds between amino acid side chains. At pH far from the optimum, the charges on these side chains are altered, disrupting the bonds that maintain the active site shape. The active site becomes denatured and can no longer bind to the substrate, so fewer enzyme-substrate complexes form and the rate of reaction drops.
解释为什么在 pH 9 时酶活性下降。酶是具有特定三维结构的蛋白质。活性位点由氨基酸侧链之间的离子键和氢键维持。当 pH 远离最适值时，这些侧链上的电荷发生改变，破坏了维持活性位点形状的键。活性位点变性，无法再与底物结合，因此形成的酶-底物复合物减少，反应速率下降。
3. Analyzing Data: Line Graphs and Trends | 数据分析：折线图与趋势
Many case studies require you to plot or interpret a line graph. When plotting, remember to label axes with quantity and unit, choose a suitable scale, and draw a smooth curve or line of best fit. In an exam, you might be given a graph showing the effect of temperature on enzyme activity. Look for the optimum temperature — the peak of the curve — and be ready to describe the shape before and after that point.
许多案例分析要求你绘制或解读折线图。绘图时，记住用物理量和单位标注坐标轴，选择合适的刻度，并绘制平滑曲线或最佳拟合线。在考试中，你可能看到一张显示温度对酶活性影响的图形。注意最适温度——曲线的峰值——并准备描述该点前后的形状。
If the curve rises steadily then falls rapidly, link this to kinetic theory and denaturation. For example: ‘As temperature rises from 10 °C to 40 °C, enzyme and substrate molecules gain kinetic energy, collide more frequently, and more enzyme-substrate complexes form, increasing the rate. Above 40 °C, the enzyme begins to denature — the active site changes shape irreversibly — so the rate falls despite high collision frequency.’
如果曲线稳步上升然后迅速下降，则将其与动力学理论和变性联系起来。例如：“当温度从 10 °C 升至 40 °C 时，酶和底物分子获得动能，碰撞更频繁，形成更多酶-底物复合物，速率增加。超过 40 °C，酶开始变性——活性位点不可逆地改变形状——因此尽管碰撞频率高，速率仍下降。”
When asked to ‘evaluate’ a data set, consider reliability (repeats, outliers), validity (control variables, range of independent variable), and whether the data support a clear conclusion. For the catalase experiment, validity could be improved by using a more precise method to measure oxygen, such as a gas syringe, and by increasing the number of pH levels tested around the optimum.
当被要求“评估”一组数据时，需考虑可靠性（重复实验、异常值）、有效性（控制变量、自变量范围）以及数据是否支持明确的结论。对于过氧化氢酶实验，可以通过使用更精确的氧气测量方法（如气体注射器）以及增加最适值附近测试的 pH 水平数量来提高有效性。
4. Case Study 2: Investigating Photosynthesis | 案例2：探究光合作用
A student used aquatic pondweed to investigate the effect of light intensity on the rate of photosynthesis. The pondweed was placed in a beaker of water, and a lamp was moved to different distances from the plant. The number of gas bubbles produced per minute was counted. The results were recorded in a table.
一名学生利用水生水草研究光照强度对光合作用速率的影响。水草放在一个装水的烧杯中，将一盏灯移动到离植物不同距离处。计数每分钟产生的气泡数量。结果记录在表中。
| Distance from lamp / cm | Bubbles per minute |
|---|---|
| 10 | 36 |
| 20 | 27 |
| 30 | 20 |
| 40 | 11 |
| 50 | 4 |
Describe the relationship between distance from the lamp and bubble count. As distance increases, the number of bubbles per minute decreases. This is because light intensity is inversely proportional to the square of the distance — doubling the distance reduces intensity to one quarter. However, the trend is not perfectly linear, and at short distances the rate might level off if another factor becomes limiting, like carbon dioxide availability.
描述灯距离与气泡计数之间的关系。随着距离增加，每分钟气泡数量减少。这是因为光强度与距离的平方成反比——距离加倍，强度降至四分之一。然而，趋势并非完全线性，在短距离时如果另一个因素（如二氧化碳浓度）成为限制因子，速率可能会趋于平稳。
Calculate the percentage decrease in bubble count when the lamp is moved from 20 cm to 50 cm. Use the formula: percentage decrease = (original value – new value) ÷ original value × 100. Substituting: (27 – 4) ÷ 27 × 100 = 85.2% decrease. This large drop highlights how crucial light intensity is for the light-dependent reactions of photosynthesis, where light energy splits water molecules and generates ATP and reduced NADP.
计算当灯从 20 cm 移到 50 cm 时气泡计数的百分比下降。使用公式：百分比下降 = (初始值 – 新值) ÷ 初始值 × 100。代入数据：(27 – 4) ÷ 27 × 100 = 85.2% 的下降。这一大幅下降突显了光强度对于光合作用光反应阶段的关键性，在光反应中，光能分解水分子并生成 ATP 和还原型 NADP。
5. Evaluating Experimental Design | 评估实验设计
In case studies, you are often asked to critique the method. Common weaknesses include lack of a control group, small sample size, not repeating measurements, and failure to control confounding variables. For the photosynthesis investigation, one flaw is that bubbles may be of different sizes, making them an unreliable measure of oxygen volume. A gas syringe connected directly to the pondweed would give more accurate volume data.
在案例分析中，你经常需要评判实验方法。常见的不足之处包括缺乏对照组、样本量小、未重复测量以及未能控制混杂变量。对于光合作用探究，一个缺陷是气泡大小可能不同，使其成为不可靠的氧气体积衡量指标。将气体注射器直接连接到水草上可提供更准确的体积数据。
Another important variable to control is the temperature — the lamp also emits heat, which could increase the rate of photosynthesis as well. To control this, a heat shield (a transparent container of water) should be placed between the lamp and the plant. Carbon dioxide concentration should also be kept constant, perhaps by adding a fixed amount of sodium hydrogen carbonate to the water.
另一个需要控制的重要变量是温度——灯也会散发热量，这会同样提高光合作用速率。为控制这一点，应在灯与植物之间放置一个隔热屏（一个透明的盛水容器）。二氧化碳浓度也应保持恒定，可通过向水中加入固定量的碳酸氢钠来实现。
When you are asked to ‘suggest improvements’, always link your suggestion to the increase in validity, accuracy, or repeatability. For example: ‘The student could repeat the experiment three times at each distance and calculate a mean. This would reduce the effect of random errors and make the results more repeatable.’
当你被要求“提出改进建议”时，务必将你的建议与提高有效性、准确性或重复性联系起来。例如：“学生可以在每个距离下重复实验三次并计算平均值。这将减少随机误差的影响，使结果更具可重复性。”
6. Case Study 3: Infectious Disease Outbreak | 案例3：传染病暴发
Analyse the following scenario: In a small town, 150 residents attended a community barbecue. Over the next three days, 45 people developed severe diarrhoea and vomiting. Stool samples were tested, and the bacterium Campylobacter jejuni was identified. Public health officials traced the source to undercooked chicken served at the event.
分析以下情境：在一个小镇上，150 名居民参加了一次社区烧烤活动。在接下来的三天里，45 人出现严重腹泻和呕吐。粪便样本检测中鉴定出空肠弯曲杆菌。公共卫生官员将源头追溯至活动中供应的未煮熟鸡肉。
Calculate the attack rate: number of cases ÷ number at risk × 100 = 45 ÷ 150 × 100 = 30%. This is a common measure in epidemiology. Campylobacter is a bacterium that invades the lining of the large intestine, causing inflammation and secretion of water into the gut, leading to diarrhoea. The toxin it produces damages host cells.
计算罹患率：病例数 ÷ 暴露人数 × 100 = 45 ÷ 150 × 100 = 30%。这是流行病学中常用指标。空肠弯曲杆菌是一种侵入大肠内壁的细菌，引发炎症并促使水分分泌到肠道中，导致腹泻。它产生的毒素会损害宿主细胞。
Explain why undercooking chicken likely caused the outbreak. Campylobacter bacteria are commonly found in the intestines of poultry. If chicken is not cooked to a core temperature of at least 75 °C, the bacteria can survive. Once ingested, they multiply in the human digestive system. Cooking denatures bacterial proteins and kills the microorganisms, so proper food hygiene is crucial.
解释为何未煮熟的鸡肉可能导致暴发。空肠弯曲杆菌常见于家禽肠道。如果鸡肉未烹饪至中心温度至少 75 °C，细菌可能存活。一旦摄入，它们会在人类消化系统内繁殖。烹饪会使细菌蛋白质变性并杀死微生物，因此适当的食品卫生至关重要。
Suggest control measures to prevent similar outbreaks. The local council could enforce stricter food safety regulations at community events, including temperature monitoring of cooking equipment. Public education about thorough cooking and avoiding cross-contamination between raw meat and ready-to-eat foods would also reduce risk. In addition, handwashing with soap after handling raw chicken is a simple, effective barrier.
建议预防类似暴发的控制措施。地方政务委员会可在社区活动中执行更严格的食品安全规定，包括监控烹饪设备的温度。向公众开展彻底烹饪、避免生肉与即食食品交叉污染的教育也能降低风险。此外，处理生鸡肉后用肥皂洗手是简单有效的屏障。
7. Using Calculations in Biology: Rates and Percentages | 生物学计算：速率与百分比
Numerical skills are tested throughout Eduqas case studies. You may need to calculate rates, percentage change, or magnification. For rates, the general formula is:
计算能力在 Eduqas 案例分析中会全程考查。你可能需要计算速率、百分比变化或放大倍数。对于速率，通用公式为：
Rate = Quantity of product formed ÷ Time taken
For example, in the catalase experiment at pH 7, 47 cm³ of oxygen was produced in 60 seconds, so the rate = 47 ÷ 60 ≈ 0.78 cm³/s. Always state units clearly. If asked to calculate the rate from a graph, choose a linear portion, draw a tangent if the graph is curved, and work out the gradient: change in y ÷ change in x.
例如，在过氧化氢酶实验中，pH 7 时 60 秒内产生 47 cm³ 氧气，因此速率 = 47 ÷ 60 ≈ 0.78 cm³/s。务必明确标注单位。如果要求根据图形计算速率，选择线性部分，若曲线为曲线图则作切线，并计算梯度：y 变化量 ÷ x 变化量。
Magnification is often calculated using the equation:
放大倍数通常使用以下方程计算：
Magnification = Image size ÷ Actual size
Ensure both measurements are in the same units before dividing. If a micrograph shows a cell image length of 50 mm and the actual cell length is 0.05 mm, magnification = 50 ÷ 0.05 = ×1000. A common mistake is forgetting unit conversion; remember that 1 mm = 1000 µm.
确保两个测量值单位相同后再进行除法运算。如果显微照片显示细胞图像长度为 50 mm，而细胞实际长度为 0.05 mm，则放大倍数 = 50 ÷ 0.05 = ×1000。常见错误是忘记单位换算；记住 1 mm = 1000 µm。
8. Case Study 4: Predator-Prey Relationships | 案例4：捕食者-猎物关系
Consider a case study from a freshwater ecosystem where scientists recorded the population sizes of water fleas (Daphnia) and a predator, the three-spined stickleback, over 12 months. The data are plotted as two overlapping curves on the same axes.
考虑一个淡水生态系统的案例研究，科学家在 12 个月内记录了水蚤（Daphnia）及其捕食者三刺鱼的数量。数据在同一坐标轴上绘制为两条重叠的曲线。
Interpret the graph: As the prey population increases, the predator population also increases after a time lag. This is because more food is available, so predators survive and reproduce. However, as predators become abundant, they consume more prey, causing the prey population to decline. The predator population then declines due to food shortage, allowing the prey to recover. This pattern is a classic predator-prey cycle.
解读图形：随着猎物种群数量增加，捕食者种群数量在一段时间滞后后也增加。这是因为食物供应更充足，捕食者得以存活并繁殖。然而，随着捕食者数量充足，它们会消耗更多猎物，导致猎物种群数量下降。然后由于食物短缺，捕食者数量下降，使猎物得以恢复。这一模式是典型的捕食者-猎物循环。
Explain why the peaks in predator numbers always occur after the peaks in prey numbers. The delay is due to the time needed for the predator population to respond reproductively to increased food supply. Gestation, growth to maturity, and birth rates mean that predator numbers cannot rise instantly when prey becomes abundant; they lag behind.
解释为何捕食者数量峰值总是出现在猎物数量峰值之后。延迟是由于捕食者种群需要时间通过繁殖来响应食物供应的增加。妊娠期、生长发育至成熟以及出生率意味着当猎物变得充足时，捕食者数量无法立即上升；它们存在滞后。
Evaluate the limitations of this simple model in the real world. In reality, populations are influenced by many other factors: disease, competition, immigration, emigration, and abiotic factors like temperature and dissolved oxygen. The cyclical pattern is often less regular than predicted. Case study questions might ask you to suggest why a real data set deviates from the idealised model.
评估这个简单模型在现实世界中的局限性。实际上，种群数量受许多其他因素影响：疾病、竞争、迁入、迁出以及温度、溶解氧等非生物因素。循环模式通常不如预测的那样规律。案例分析题可能会要求你建议为什么真实数据会偏离理想化模型。
9. Drawing Conclusions and Making Predictions | 得出结论与预测
After analysing data, you must draw a conclusion that directly addresses the original hypothesis or question. For example, if the hypothesis was ‘Light intensity affects the rate of photosynthesis’, the conclusion should state: ‘As light intensity increased, the rate of photosynthesis increased, up to a point. This supports the hypothesis.’ If the results are not fully conclusive, you must acknowledge limitations: ‘The hypothesis is partially supported, but further investigation with a wider range of light intensities is needed.’
分析数据后，你必须得出直接回应原始假设或问题的结论。例如，如果假设是“光照强度影响光合作用速率”，结论应表述为：“随着光照强度增加，光合作用速率上升，直至某一点。这支持了假设。”如果结果并非完全确凿，必须承认局限性：“假设得到部分支持，但需要用更广的光照强度范围作进一步研究。”
Making predictions based on evidence is another common task. If the catalase enzyme had an optimum at pH 7, you might predict that at pH 7.5 the activity would be slightly lower than at pH 7, but still higher than at pH 8. This prediction is based on the trend already observed. Always justify your prediction with reference to the data.
根据证据进行预测是另一项常见任务。如果过氧化氢酶的最适 pH 为 7，你可能预测在 pH 7.5 时活性会略低于 pH 7，但仍高于 pH 8。这一预测基于已观察到的趋势。始终引用数据来证明你的预测理由。
When a case study includes anomalous results, you need to identify and explain them. Perhaps one bubble count at 30 cm was unusually high; this could be due to a temporary rise in temperature, an extra shake of the test tube mixing the solution, or counting error. Anomalous points should be excluded from a mean calculation and the experiment repeated.
当案例研究包含异常结果时，你需要识别并解释它们。也许 30 cm 处有一个气泡计数异常高；这可能是由于温度暂时升高、额外摇晃试管使溶液混合或计数错误。计算平均值时应排除异常点并重复实验。
10. Revision Tips for Case Studies | 案例研究复习贴士
Mastering case studies is about practising the application of knowledge, not just passive reading. Create your own mini-case studies: take a biological concept — for instance, transpiration — and design a simple experiment, recording ‘data’ and then writing likely exam questions and model answers. This active learning technique reinforces both content and skills.
掌握案例研究的关键在于练习应用知识，而不仅仅是被动阅读。创建你自己的小型案例研究：选取一个生物学概念——例如蒸腾作用——设计一个简单的实验，记录“数据”，然后撰写可能的考试问题和标准答案。这种主动学习技巧能同时强化内容和技能。
Always link back to the key principles when explaining trends. Whether you are discussing enzymes, diffusion, photosynthesis, or immune responses, the underlying science is what earns marks. Use precise vocabulary: ‘denatured’, ‘active site’, ‘limiting factor’, ‘pathogen’, ‘antibodies’, ‘vaccine’. Practise writing explanations in bullet points under timed conditions.
在解释趋势时，始终联系关键原理。无论你讨论的是酶、扩散、光合作用还是免疫反应，科学的底层逻辑才是得分点。使用准确的词汇：“变性”、“活性位点”、“限制因子”、“病原体”、“抗体”、“疫苗”。练习在计时条件下以要点形式撰写解释。
Finally, if you come across an unfamiliar context in the exam, stay calm. Identify which topic area the case study belongs to — is it about cells, plants, ecology, or disease? Then recall the relevant core knowledge. The mark scheme will reward sensible suggestions that demonstrate biological thinking, even if they are not the expected answer. So, be curious, be logical, and show the examiner how you think like a biologist.
最后，如果在考试中遇到不熟悉的情境，保持冷静。确定该案例研究属于哪个主题领域——是关于细胞、植物、生态还是疾病？然后回忆相关的核心知识。评分标准会奖励合理的建议，即使它们并非预期的答案，只要展现出生物学思维即可。因此，保持好奇、保持逻辑，并向考官展示你如何像生物学家一样思考。
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